git.sesse.net Git - bcachefs-tools-debian/blob - libbcachefs/btree_gc.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2010 Kent Overstreet <kent.overstreet@gmail.com>
   4  * Copyright (C) 2014 Datera Inc.
   5  */
   6
   7 #include "bcachefs.h"
   8 #include "alloc_background.h"
   9 #include "alloc_foreground.h"
  10 #include "bkey_methods.h"
  11 #include "bkey_buf.h"
  12 #include "btree_key_cache.h"
  13 #include "btree_locking.h"
  14 #include "btree_update_interior.h"
  15 #include "btree_io.h"
  16 #include "btree_gc.h"
  17 #include "buckets.h"
  18 #include "clock.h"
  19 #include "debug.h"
  20 #include "ec.h"
  21 #include "error.h"
  22 #include "extents.h"
  23 #include "journal.h"
  24 #include "keylist.h"
  25 #include "move.h"
  26 #include "recovery.h"
  27 #include "reflink.h"
  28 #include "replicas.h"
  29 #include "super-io.h"
  30
  31 #include <linux/slab.h>
  32 #include <linux/bitops.h>
  33 #include <linux/freezer.h>
  34 #include <linux/kthread.h>
  35 #include <linux/preempt.h>
  36 #include <linux/rcupdate.h>
  37 #include <linux/sched/task.h>
  38 #include <trace/events/bcachefs.h>
  39
  40 #define DROP_THIS_NODE          10
  41 #define DROP_PREV_NODE          11
  42
  43 static inline void __gc_pos_set(struct bch_fs *c, struct gc_pos new_pos)
  44 {
  45         preempt_disable();
  46         write_seqcount_begin(&c->gc_pos_lock);
  47         c->gc_pos = new_pos;
  48         write_seqcount_end(&c->gc_pos_lock);
  49         preempt_enable();
  50 }
  51
  52 static inline void gc_pos_set(struct bch_fs *c, struct gc_pos new_pos)
  53 {
  54         BUG_ON(gc_pos_cmp(new_pos, c->gc_pos) <= 0);
  55         __gc_pos_set(c, new_pos);
  56 }
  57
  58 /*
  59  * Missing: if an interior btree node is empty, we need to do something -
  60  * perhaps just kill it
  61  */
  62 static int bch2_gc_check_topology(struct bch_fs *c,
  63                                   struct btree *b,
  64                                   struct bkey_buf *prev,
  65                                   struct bkey_buf cur,
  66                                   bool is_last)
  67 {
  68         struct bpos node_start  = b->data->min_key;
  69         struct bpos node_end    = b->data->max_key;
  70         struct bpos expected_start = bkey_deleted(&prev->k->k)
  71                 ? node_start
  72                 : bpos_successor(prev->k->k.p);
  73         struct printbuf buf1 = PRINTBUF, buf2 = PRINTBUF;
  74         int ret = 0;
  75
  76         if (cur.k->k.type == KEY_TYPE_btree_ptr_v2) {
  77                 struct bkey_i_btree_ptr_v2 *bp = bkey_i_to_btree_ptr_v2(cur.k);
  78
  79                 if (!bpos_eq(expected_start, bp->v.min_key)) {
  80                         bch2_topology_error(c);
  81
  82                         if (bkey_deleted(&prev->k->k)) {
  83                                 prt_printf(&buf1, "start of node: ");
  84                                 bch2_bpos_to_text(&buf1, node_start);
  85                         } else {
  86                                 bch2_bkey_val_to_text(&buf1, c, bkey_i_to_s_c(prev->k));
  87                         }
  88                         bch2_bkey_val_to_text(&buf2, c, bkey_i_to_s_c(cur.k));
  89
  90                         if (__fsck_err(c,
  91                                   FSCK_CAN_FIX|
  92                                   FSCK_CAN_IGNORE|
  93                                   FSCK_NO_RATELIMIT,
  94                                   "btree node with incorrect min_key at btree %s level %u:\n"
  95                                   "  prev %s\n"
  96                                   "  cur %s",
  97                                   bch2_btree_ids[b->c.btree_id], b->c.level,
  98                                   buf1.buf, buf2.buf) &&
  99                             !test_bit(BCH_FS_TOPOLOGY_REPAIR_DONE, &c->flags)) {
 100                                 bch_info(c, "Halting mark and sweep to start topology repair pass");
 101                                 ret = -BCH_ERR_need_topology_repair;
 102                                 goto err;
 103                         } else {
 104                                 set_bit(BCH_FS_INITIAL_GC_UNFIXED, &c->flags);
 105                         }
 106                 }
 107         }
 108
 109         if (is_last && !bpos_eq(cur.k->k.p, node_end)) {
 110                 bch2_topology_error(c);
 111
 112                 printbuf_reset(&buf1);
 113                 printbuf_reset(&buf2);
 114
 115                 bch2_bkey_val_to_text(&buf1, c, bkey_i_to_s_c(cur.k));
 116                 bch2_bpos_to_text(&buf2, node_end);
 117
 118                 if (__fsck_err(c,
 119                           FSCK_CAN_FIX|
 120                           FSCK_CAN_IGNORE|
 121                           FSCK_NO_RATELIMIT,
 122                           "btree node with incorrect max_key at btree %s level %u:\n"
 123                           "  %s\n"
 124                           "  expected %s",
 125                           bch2_btree_ids[b->c.btree_id], b->c.level,
 126                           buf1.buf, buf2.buf) &&
 127                     !test_bit(BCH_FS_TOPOLOGY_REPAIR_DONE, &c->flags)) {
 128                         bch_info(c, "Halting mark and sweep to start topology repair pass");
 129                         ret = -BCH_ERR_need_topology_repair;
 130                         goto err;
 131                 } else {
 132                         set_bit(BCH_FS_INITIAL_GC_UNFIXED, &c->flags);
 133                 }
 134         }
 135
 136         bch2_bkey_buf_copy(prev, c, cur.k);
 137 err:
 138 fsck_err:
 139         printbuf_exit(&buf2);
 140         printbuf_exit(&buf1);
 141         return ret;
 142 }
 143
 144 static void btree_ptr_to_v2(struct btree *b, struct bkey_i_btree_ptr_v2 *dst)
 145 {
 146         switch (b->key.k.type) {
 147         case KEY_TYPE_btree_ptr: {
 148                 struct bkey_i_btree_ptr *src = bkey_i_to_btree_ptr(&b->key);
 149
 150                 dst->k.p                = src->k.p;
 151                 dst->v.mem_ptr          = 0;
 152                 dst->v.seq              = b->data->keys.seq;
 153                 dst->v.sectors_written  = 0;
 154                 dst->v.flags            = 0;
 155                 dst->v.min_key          = b->data->min_key;
 156                 set_bkey_val_bytes(&dst->k, sizeof(dst->v) + bkey_val_bytes(&src->k));
 157                 memcpy(dst->v.start, src->v.start, bkey_val_bytes(&src->k));
 158                 break;
 159         }
 160         case KEY_TYPE_btree_ptr_v2:
 161                 bkey_copy(&dst->k_i, &b->key);
 162                 break;
 163         default:
 164                 BUG();
 165         }
 166 }
 167
 168 static void bch2_btree_node_update_key_early(struct btree_trans *trans,
 169                                              enum btree_id btree, unsigned level,
 170                                              struct bkey_s_c old, struct bkey_i *new)
 171 {
 172         struct bch_fs *c = trans->c;
 173         struct btree *b;
 174         struct bkey_buf tmp;
 175         int ret;
 176
 177         bch2_bkey_buf_init(&tmp);
 178         bch2_bkey_buf_reassemble(&tmp, c, old);
 179
 180         b = bch2_btree_node_get_noiter(trans, tmp.k, btree, level, true);
 181         if (!IS_ERR_OR_NULL(b)) {
 182                 mutex_lock(&c->btree_cache.lock);
 183
 184                 bch2_btree_node_hash_remove(&c->btree_cache, b);
 185
 186                 bkey_copy(&b->key, new);
 187                 ret = __bch2_btree_node_hash_insert(&c->btree_cache, b);
 188                 BUG_ON(ret);
 189
 190                 mutex_unlock(&c->btree_cache.lock);
 191                 six_unlock_read(&b->c.lock);
 192         }
 193
 194         bch2_bkey_buf_exit(&tmp, c);
 195 }
 196
 197 static int set_node_min(struct bch_fs *c, struct btree *b, struct bpos new_min)
 198 {
 199         struct bkey_i_btree_ptr_v2 *new;
 200         int ret;
 201
 202         new = kmalloc_array(BKEY_BTREE_PTR_U64s_MAX, sizeof(u64), GFP_KERNEL);
 203         if (!new)
 204                 return -BCH_ERR_ENOMEM_gc_repair_key;
 205
 206         btree_ptr_to_v2(b, new);
 207         b->data->min_key        = new_min;
 208         new->v.min_key          = new_min;
 209         SET_BTREE_PTR_RANGE_UPDATED(&new->v, true);
 210
 211         ret = bch2_journal_key_insert_take(c, b->c.btree_id, b->c.level + 1, &new->k_i);
 212         if (ret) {
 213                 kfree(new);
 214                 return ret;
 215         }
 216
 217         bch2_btree_node_drop_keys_outside_node(b);
 218         bkey_copy(&b->key, &new->k_i);
 219         return 0;
 220 }
 221
 222 static int set_node_max(struct bch_fs *c, struct btree *b, struct bpos new_max)
 223 {
 224         struct bkey_i_btree_ptr_v2 *new;
 225         int ret;
 226
 227         ret = bch2_journal_key_delete(c, b->c.btree_id, b->c.level + 1, b->key.k.p);
 228         if (ret)
 229                 return ret;
 230
 231         new = kmalloc_array(BKEY_BTREE_PTR_U64s_MAX, sizeof(u64), GFP_KERNEL);
 232         if (!new)
 233                 return -BCH_ERR_ENOMEM_gc_repair_key;
 234
 235         btree_ptr_to_v2(b, new);
 236         b->data->max_key        = new_max;
 237         new->k.p                = new_max;
 238         SET_BTREE_PTR_RANGE_UPDATED(&new->v, true);
 239
 240         ret = bch2_journal_key_insert_take(c, b->c.btree_id, b->c.level + 1, &new->k_i);
 241         if (ret) {
 242                 kfree(new);
 243                 return ret;
 244         }
 245
 246         bch2_btree_node_drop_keys_outside_node(b);
 247
 248         mutex_lock(&c->btree_cache.lock);
 249         bch2_btree_node_hash_remove(&c->btree_cache, b);
 250
 251         bkey_copy(&b->key, &new->k_i);
 252         ret = __bch2_btree_node_hash_insert(&c->btree_cache, b);
 253         BUG_ON(ret);
 254         mutex_unlock(&c->btree_cache.lock);
 255         return 0;
 256 }
 257
 258 static int btree_repair_node_boundaries(struct bch_fs *c, struct btree *b,
 259                                         struct btree *prev, struct btree *cur)
 260 {
 261         struct bpos expected_start = !prev
 262                 ? b->data->min_key
 263                 : bpos_successor(prev->key.k.p);
 264         struct printbuf buf1 = PRINTBUF, buf2 = PRINTBUF;
 265         int ret = 0;
 266
 267         if (!prev) {
 268                 prt_printf(&buf1, "start of node: ");
 269                 bch2_bpos_to_text(&buf1, b->data->min_key);
 270         } else {
 271                 bch2_bkey_val_to_text(&buf1, c, bkey_i_to_s_c(&prev->key));
 272         }
 273
 274         bch2_bkey_val_to_text(&buf2, c, bkey_i_to_s_c(&cur->key));
 275
 276         if (prev &&
 277             bpos_gt(expected_start, cur->data->min_key) &&
 278             BTREE_NODE_SEQ(cur->data) > BTREE_NODE_SEQ(prev->data)) {
 279                 /* cur overwrites prev: */
 280
 281                 if (mustfix_fsck_err_on(bpos_ge(prev->data->min_key,
 282                                                 cur->data->min_key), c,
 283                                 "btree node overwritten by next node at btree %s level %u:\n"
 284                                 "  node %s\n"
 285                                 "  next %s",
 286                                 bch2_btree_ids[b->c.btree_id], b->c.level,
 287                                 buf1.buf, buf2.buf)) {
 288                         ret = DROP_PREV_NODE;
 289                         goto out;
 290                 }
 291
 292                 if (mustfix_fsck_err_on(!bpos_eq(prev->key.k.p,
 293                                                  bpos_predecessor(cur->data->min_key)), c,
 294                                 "btree node with incorrect max_key at btree %s level %u:\n"
 295                                 "  node %s\n"
 296                                 "  next %s",
 297                                 bch2_btree_ids[b->c.btree_id], b->c.level,
 298                                 buf1.buf, buf2.buf))
 299                         ret = set_node_max(c, prev,
 300                                            bpos_predecessor(cur->data->min_key));
 301         } else {
 302                 /* prev overwrites cur: */
 303
 304                 if (mustfix_fsck_err_on(bpos_ge(expected_start,
 305                                                 cur->data->max_key), c,
 306                                 "btree node overwritten by prev node at btree %s level %u:\n"
 307                                 "  prev %s\n"
 308                                 "  node %s",
 309                                 bch2_btree_ids[b->c.btree_id], b->c.level,
 310                                 buf1.buf, buf2.buf)) {
 311                         ret = DROP_THIS_NODE;
 312                         goto out;
 313                 }
 314
 315                 if (mustfix_fsck_err_on(!bpos_eq(expected_start, cur->data->min_key), c,
 316                                 "btree node with incorrect min_key at btree %s level %u:\n"
 317                                 "  prev %s\n"
 318                                 "  node %s",
 319                                 bch2_btree_ids[b->c.btree_id], b->c.level,
 320                                 buf1.buf, buf2.buf))
 321                         ret = set_node_min(c, cur, expected_start);
 322         }
 323 out:
 324 fsck_err:
 325         printbuf_exit(&buf2);
 326         printbuf_exit(&buf1);
 327         return ret;
 328 }
 329
 330 static int btree_repair_node_end(struct bch_fs *c, struct btree *b,
 331                                  struct btree *child)
 332 {
 333         struct printbuf buf1 = PRINTBUF, buf2 = PRINTBUF;
 334         int ret = 0;
 335
 336         bch2_bkey_val_to_text(&buf1, c, bkey_i_to_s_c(&child->key));
 337         bch2_bpos_to_text(&buf2, b->key.k.p);
 338
 339         if (mustfix_fsck_err_on(!bpos_eq(child->key.k.p, b->key.k.p), c,
 340                         "btree node with incorrect max_key at btree %s level %u:\n"
 341                         "  %s\n"
 342                         "  expected %s",
 343                         bch2_btree_ids[b->c.btree_id], b->c.level,
 344                         buf1.buf, buf2.buf)) {
 345                 ret = set_node_max(c, child, b->key.k.p);
 346                 if (ret)
 347                         goto err;
 348         }
 349 err:
 350 fsck_err:
 351         printbuf_exit(&buf2);
 352         printbuf_exit(&buf1);
 353         return ret;
 354 }
 355
 356 static int bch2_btree_repair_topology_recurse(struct btree_trans *trans, struct btree *b)
 357 {
 358         struct bch_fs *c = trans->c;
 359         struct btree_and_journal_iter iter;
 360         struct bkey_s_c k;
 361         struct bkey_buf prev_k, cur_k;
 362         struct btree *prev = NULL, *cur = NULL;
 363         bool have_child, dropped_children = false;
 364         struct printbuf buf = PRINTBUF;
 365         int ret = 0;
 366
 367         if (!b->c.level)
 368                 return 0;
 369 again:
 370         prev = NULL;
 371         have_child = dropped_children = false;
 372         bch2_bkey_buf_init(&prev_k);
 373         bch2_bkey_buf_init(&cur_k);
 374         bch2_btree_and_journal_iter_init_node_iter(&iter, c, b);
 375
 376         while ((k = bch2_btree_and_journal_iter_peek(&iter)).k) {
 377                 BUG_ON(bpos_lt(k.k->p, b->data->min_key));
 378                 BUG_ON(bpos_gt(k.k->p, b->data->max_key));
 379
 380                 bch2_btree_and_journal_iter_advance(&iter);
 381                 bch2_bkey_buf_reassemble(&cur_k, c, k);
 382
 383                 cur = bch2_btree_node_get_noiter(trans, cur_k.k,
 384                                         b->c.btree_id, b->c.level - 1,
 385                                         false);
 386                 ret = PTR_ERR_OR_ZERO(cur);
 387
 388                 printbuf_reset(&buf);
 389                 bch2_bkey_val_to_text(&buf, c, bkey_i_to_s_c(cur_k.k));
 390
 391                 if (mustfix_fsck_err_on(ret == -EIO, c,
 392                                 "Topology repair: unreadable btree node at btree %s level %u:\n"
 393                                 "  %s",
 394                                 bch2_btree_ids[b->c.btree_id],
 395                                 b->c.level - 1,
 396                                 buf.buf)) {
 397                         bch2_btree_node_evict(trans, cur_k.k);
 398                         ret = bch2_journal_key_delete(c, b->c.btree_id,
 399                                                       b->c.level, cur_k.k->k.p);
 400                         cur = NULL;
 401                         if (ret)
 402                                 break;
 403                         continue;
 404                 }
 405
 406                 if (ret) {
 407                         bch_err(c, "%s: error getting btree node: %s",
 408                                 __func__, bch2_err_str(ret));
 409                         break;
 410                 }
 411
 412                 ret = btree_repair_node_boundaries(c, b, prev, cur);
 413
 414                 if (ret == DROP_THIS_NODE) {
 415                         six_unlock_read(&cur->c.lock);
 416                         bch2_btree_node_evict(trans, cur_k.k);
 417                         ret = bch2_journal_key_delete(c, b->c.btree_id,
 418                                                       b->c.level, cur_k.k->k.p);
 419                         cur = NULL;
 420                         if (ret)
 421                                 break;
 422                         continue;
 423                 }
 424
 425                 if (prev)
 426                         six_unlock_read(&prev->c.lock);
 427                 prev = NULL;
 428
 429                 if (ret == DROP_PREV_NODE) {
 430                         bch2_btree_node_evict(trans, prev_k.k);
 431                         ret = bch2_journal_key_delete(c, b->c.btree_id,
 432                                                       b->c.level, prev_k.k->k.p);
 433                         if (ret)
 434                                 break;
 435
 436                         bch2_btree_and_journal_iter_exit(&iter);
 437                         bch2_bkey_buf_exit(&prev_k, c);
 438                         bch2_bkey_buf_exit(&cur_k, c);
 439                         goto again;
 440                 } else if (ret)
 441                         break;
 442
 443                 prev = cur;
 444                 cur = NULL;
 445                 bch2_bkey_buf_copy(&prev_k, c, cur_k.k);
 446         }
 447
 448         if (!ret && !IS_ERR_OR_NULL(prev)) {
 449                 BUG_ON(cur);
 450                 ret = btree_repair_node_end(c, b, prev);
 451         }
 452
 453         if (!IS_ERR_OR_NULL(prev))
 454                 six_unlock_read(&prev->c.lock);
 455         prev = NULL;
 456         if (!IS_ERR_OR_NULL(cur))
 457                 six_unlock_read(&cur->c.lock);
 458         cur = NULL;
 459
 460         if (ret)
 461                 goto err;
 462
 463         bch2_btree_and_journal_iter_exit(&iter);
 464         bch2_btree_and_journal_iter_init_node_iter(&iter, c, b);
 465
 466         while ((k = bch2_btree_and_journal_iter_peek(&iter)).k) {
 467                 bch2_bkey_buf_reassemble(&cur_k, c, k);
 468                 bch2_btree_and_journal_iter_advance(&iter);
 469
 470                 cur = bch2_btree_node_get_noiter(trans, cur_k.k,
 471                                         b->c.btree_id, b->c.level - 1,
 472                                         false);
 473                 ret = PTR_ERR_OR_ZERO(cur);
 474
 475                 if (ret) {
 476                         bch_err(c, "%s: error getting btree node: %s",
 477                                 __func__, bch2_err_str(ret));
 478                         goto err;
 479                 }
 480
 481                 ret = bch2_btree_repair_topology_recurse(trans, cur);
 482                 six_unlock_read(&cur->c.lock);
 483                 cur = NULL;
 484
 485                 if (ret == DROP_THIS_NODE) {
 486                         bch2_btree_node_evict(trans, cur_k.k);
 487                         ret = bch2_journal_key_delete(c, b->c.btree_id,
 488                                                       b->c.level, cur_k.k->k.p);
 489                         dropped_children = true;
 490                 }
 491
 492                 if (ret)
 493                         goto err;
 494
 495                 have_child = true;
 496         }
 497
 498         printbuf_reset(&buf);
 499         bch2_bkey_val_to_text(&buf, c, bkey_i_to_s_c(&b->key));
 500
 501         if (mustfix_fsck_err_on(!have_child, c,
 502                         "empty interior btree node at btree %s level %u\n"
 503                         "  %s",
 504                         bch2_btree_ids[b->c.btree_id],
 505                         b->c.level, buf.buf))
 506                 ret = DROP_THIS_NODE;
 507 err:
 508 fsck_err:
 509         if (!IS_ERR_OR_NULL(prev))
 510                 six_unlock_read(&prev->c.lock);
 511         if (!IS_ERR_OR_NULL(cur))
 512                 six_unlock_read(&cur->c.lock);
 513
 514         bch2_btree_and_journal_iter_exit(&iter);
 515         bch2_bkey_buf_exit(&prev_k, c);
 516         bch2_bkey_buf_exit(&cur_k, c);
 517
 518         if (!ret && dropped_children)
 519                 goto again;
 520
 521         printbuf_exit(&buf);
 522         return ret;
 523 }
 524
 525 static int bch2_repair_topology(struct bch_fs *c)
 526 {
 527         struct btree_trans trans;
 528         struct btree *b;
 529         unsigned i;
 530         int ret = 0;
 531
 532         bch2_trans_init(&trans, c, 0, 0);
 533
 534         for (i = 0; i < BTREE_ID_NR && !ret; i++) {
 535                 b = c->btree_roots[i].b;
 536                 if (btree_node_fake(b))
 537                         continue;
 538
 539                 btree_node_lock_nopath_nofail(&trans, &b->c, SIX_LOCK_read);
 540                 ret = bch2_btree_repair_topology_recurse(&trans, b);
 541                 six_unlock_read(&b->c.lock);
 542
 543                 if (ret == DROP_THIS_NODE) {
 544                         bch_err(c, "empty btree root - repair unimplemented");
 545                         ret = -BCH_ERR_fsck_repair_unimplemented;
 546                 }
 547         }
 548
 549         bch2_trans_exit(&trans);
 550
 551         return ret;
 552 }
 553
 554 static int bch2_check_fix_ptrs(struct btree_trans *trans, enum btree_id btree_id,
 555                                unsigned level, bool is_root,
 556                                struct bkey_s_c *k)
 557 {
 558         struct bch_fs *c = trans->c;
 559         struct bkey_ptrs_c ptrs = bch2_bkey_ptrs_c(*k);
 560         const union bch_extent_entry *entry;
 561         struct extent_ptr_decoded p = { 0 };
 562         bool do_update = false;
 563         struct printbuf buf = PRINTBUF;
 564         int ret = 0;
 565
 566         /*
 567          * XXX
 568          * use check_bucket_ref here
 569          */
 570         bkey_for_each_ptr_decode(k->k, ptrs, p, entry) {
 571                 struct bch_dev *ca = bch_dev_bkey_exists(c, p.ptr.dev);
 572                 struct bucket *g = PTR_GC_BUCKET(ca, &p.ptr);
 573                 enum bch_data_type data_type = bch2_bkey_ptr_data_type(*k, &entry->ptr);
 574
 575                 if (c->opts.reconstruct_alloc ||
 576                     fsck_err_on(!g->gen_valid, c,
 577                                 "bucket %u:%zu data type %s ptr gen %u missing in alloc btree\n"
 578                                 "while marking %s",
 579                                 p.ptr.dev, PTR_BUCKET_NR(ca, &p.ptr),
 580                                 bch2_data_types[ptr_data_type(k->k, &p.ptr)],
 581                                 p.ptr.gen,
 582                                 (printbuf_reset(&buf),
 583                                  bch2_bkey_val_to_text(&buf, c, *k), buf.buf))) {
 584                         if (!p.ptr.cached) {
 585                                 g->gen_valid            = true;
 586                                 g->gen                  = p.ptr.gen;
 587                         } else {
 588                                 do_update = true;
 589                         }
 590                 }
 591
 592                 if (fsck_err_on(gen_cmp(p.ptr.gen, g->gen) > 0, c,
 593                                 "bucket %u:%zu data type %s ptr gen in the future: %u > %u\n"
 594                                 "while marking %s",
 595                                 p.ptr.dev, PTR_BUCKET_NR(ca, &p.ptr),
 596                                 bch2_data_types[ptr_data_type(k->k, &p.ptr)],
 597                                 p.ptr.gen, g->gen,
 598                                 (printbuf_reset(&buf),
 599                                  bch2_bkey_val_to_text(&buf, c, *k), buf.buf))) {
 600                         if (!p.ptr.cached) {
 601                                 g->gen_valid            = true;
 602                                 g->gen                  = p.ptr.gen;
 603                                 g->data_type            = 0;
 604                                 g->dirty_sectors        = 0;
 605                                 g->cached_sectors       = 0;
 606                                 set_bit(BCH_FS_NEED_ANOTHER_GC, &c->flags);
 607                         } else {
 608                                 do_update = true;
 609                         }
 610                 }
 611
 612                 if (fsck_err_on(gen_cmp(g->gen, p.ptr.gen) > BUCKET_GC_GEN_MAX, c,
 613                                 "bucket %u:%zu gen %u data type %s: ptr gen %u too stale\n"
 614                                 "while marking %s",
 615                                 p.ptr.dev, PTR_BUCKET_NR(ca, &p.ptr), g->gen,
 616                                 bch2_data_types[ptr_data_type(k->k, &p.ptr)],
 617                                 p.ptr.gen,
 618                                 (printbuf_reset(&buf),
 619                                  bch2_bkey_val_to_text(&buf, c, *k), buf.buf)))
 620                         do_update = true;
 621
 622                 if (fsck_err_on(!p.ptr.cached &&
 623                                 gen_cmp(p.ptr.gen, g->gen) < 0, c,
 624                                 "bucket %u:%zu data type %s stale dirty ptr: %u < %u\n"
 625                                 "while marking %s",
 626                                 p.ptr.dev, PTR_BUCKET_NR(ca, &p.ptr),
 627                                 bch2_data_types[ptr_data_type(k->k, &p.ptr)],
 628                                 p.ptr.gen, g->gen,
 629                                 (printbuf_reset(&buf),
 630                                  bch2_bkey_val_to_text(&buf, c, *k), buf.buf)))
 631                         do_update = true;
 632
 633                 if (data_type != BCH_DATA_btree && p.ptr.gen != g->gen)
 634                         continue;
 635
 636                 if (fsck_err_on(bucket_data_type(g->data_type) &&
 637                                 bucket_data_type(g->data_type) != data_type, c,
 638                                 "bucket %u:%zu different types of data in same bucket: %s, %s\n"
 639                                 "while marking %s",
 640                                 p.ptr.dev, PTR_BUCKET_NR(ca, &p.ptr),
 641                                 bch2_data_types[g->data_type],
 642                                 bch2_data_types[data_type],
 643                                 (printbuf_reset(&buf),
 644                                  bch2_bkey_val_to_text(&buf, c, *k), buf.buf))) {
 645                         if (data_type == BCH_DATA_btree) {
 646                                 g->data_type    = data_type;
 647                                 set_bit(BCH_FS_NEED_ANOTHER_GC, &c->flags);
 648                         } else {
 649                                 do_update = true;
 650                         }
 651                 }
 652
 653                 if (p.has_ec) {
 654                         struct gc_stripe *m = genradix_ptr(&c->gc_stripes, p.ec.idx);
 655
 656                         if (fsck_err_on(!m || !m->alive, c,
 657                                         "pointer to nonexistent stripe %llu\n"
 658                                         "while marking %s",
 659                                         (u64) p.ec.idx,
 660                                         (printbuf_reset(&buf),
 661                                          bch2_bkey_val_to_text(&buf, c, *k), buf.buf)))
 662                                 do_update = true;
 663
 664                         if (fsck_err_on(m && m->alive && !bch2_ptr_matches_stripe_m(m, p), c,
 665                                         "pointer does not match stripe %llu\n"
 666                                         "while marking %s",
 667                                         (u64) p.ec.idx,
 668                                         (printbuf_reset(&buf),
 669                                          bch2_bkey_val_to_text(&buf, c, *k), buf.buf)))
 670                                 do_update = true;
 671                 }
 672         }
 673
 674         if (do_update) {
 675                 struct bkey_ptrs ptrs;
 676                 union bch_extent_entry *entry;
 677                 struct bch_extent_ptr *ptr;
 678                 struct bkey_i *new;
 679
 680                 if (is_root) {
 681                         bch_err(c, "cannot update btree roots yet");
 682                         ret = -EINVAL;
 683                         goto err;
 684                 }
 685
 686                 new = kmalloc(bkey_bytes(k->k), GFP_KERNEL);
 687                 if (!new) {
 688                         bch_err(c, "%s: error allocating new key", __func__);
 689                         ret = -BCH_ERR_ENOMEM_gc_repair_key;
 690                         goto err;
 691                 }
 692
 693                 bkey_reassemble(new, *k);
 694
 695                 if (level) {
 696                         /*
 697                          * We don't want to drop btree node pointers - if the
 698                          * btree node isn't there anymore, the read path will
 699                          * sort it out:
 700                          */
 701                         ptrs = bch2_bkey_ptrs(bkey_i_to_s(new));
 702                         bkey_for_each_ptr(ptrs, ptr) {
 703                                 struct bch_dev *ca = bch_dev_bkey_exists(c, ptr->dev);
 704                                 struct bucket *g = PTR_GC_BUCKET(ca, ptr);
 705
 706                                 ptr->gen = g->gen;
 707                         }
 708                 } else {
 709                         bch2_bkey_drop_ptrs(bkey_i_to_s(new), ptr, ({
 710                                 struct bch_dev *ca = bch_dev_bkey_exists(c, ptr->dev);
 711                                 struct bucket *g = PTR_GC_BUCKET(ca, ptr);
 712                                 enum bch_data_type data_type = bch2_bkey_ptr_data_type(*k, ptr);
 713
 714                                 (ptr->cached &&
 715                                  (!g->gen_valid || gen_cmp(ptr->gen, g->gen) > 0)) ||
 716                                 (!ptr->cached &&
 717                                  gen_cmp(ptr->gen, g->gen) < 0) ||
 718                                 gen_cmp(g->gen, ptr->gen) > BUCKET_GC_GEN_MAX ||
 719                                 (g->data_type &&
 720                                  g->data_type != data_type);
 721                         }));
 722 again:
 723                         ptrs = bch2_bkey_ptrs(bkey_i_to_s(new));
 724                         bkey_extent_entry_for_each(ptrs, entry) {
 725                                 if (extent_entry_type(entry) == BCH_EXTENT_ENTRY_stripe_ptr) {
 726                                         struct gc_stripe *m = genradix_ptr(&c->gc_stripes,
 727                                                                         entry->stripe_ptr.idx);
 728                                         union bch_extent_entry *next_ptr;
 729
 730                                         bkey_extent_entry_for_each_from(ptrs, next_ptr, entry)
 731                                                 if (extent_entry_type(next_ptr) == BCH_EXTENT_ENTRY_ptr)
 732                                                         goto found;
 733                                         next_ptr = NULL;
 734 found:
 735                                         if (!next_ptr) {
 736                                                 bch_err(c, "aieee, found stripe ptr with no data ptr");
 737                                                 continue;
 738                                         }
 739
 740                                         if (!m || !m->alive ||
 741                                             !__bch2_ptr_matches_stripe(&m->ptrs[entry->stripe_ptr.block],
 742                                                                        &next_ptr->ptr,
 743                                                                        m->sectors)) {
 744                                                 bch2_bkey_extent_entry_drop(new, entry);
 745                                                 goto again;
 746                                         }
 747                                 }
 748                         }
 749                 }
 750
 751                 ret = bch2_journal_key_insert_take(c, btree_id, level, new);
 752                 if (ret) {
 753                         kfree(new);
 754                         goto err;
 755                 }
 756
 757                 if (level)
 758                         bch2_btree_node_update_key_early(trans, btree_id, level - 1, *k, new);
 759
 760                 if (c->opts.verbose) {
 761                         printbuf_reset(&buf);
 762                         bch2_bkey_val_to_text(&buf, c, *k);
 763                         bch_info(c, "updated %s", buf.buf);
 764
 765                         printbuf_reset(&buf);
 766                         bch2_bkey_val_to_text(&buf, c, bkey_i_to_s_c(new));
 767                         bch_info(c, "new key %s", buf.buf);
 768                 }
 769
 770                 *k = bkey_i_to_s_c(new);
 771         }
 772 err:
 773 fsck_err:
 774         printbuf_exit(&buf);
 775         return ret;
 776 }
 777
 778 /* marking of btree keys/nodes: */
 779
 780 static int bch2_gc_mark_key(struct btree_trans *trans, enum btree_id btree_id,
 781                             unsigned level, bool is_root,
 782                             struct bkey_s_c *k,
 783                             bool initial)
 784 {
 785         struct bch_fs *c = trans->c;
 786         struct bkey deleted = KEY(0, 0, 0);
 787         struct bkey_s_c old = (struct bkey_s_c) { &deleted, NULL };
 788         unsigned flags =
 789                 BTREE_TRIGGER_GC|
 790                 (initial ? BTREE_TRIGGER_NOATOMIC : 0);
 791         int ret = 0;
 792
 793         deleted.p = k->k->p;
 794
 795         if (initial) {
 796                 BUG_ON(bch2_journal_seq_verify &&
 797                        k->k->version.lo > atomic64_read(&c->journal.seq));
 798
 799                 ret = bch2_check_fix_ptrs(trans, btree_id, level, is_root, k);
 800                 if (ret)
 801                         goto err;
 802
 803                 if (fsck_err_on(k->k->version.lo > atomic64_read(&c->key_version), c,
 804                                 "key version number higher than recorded: %llu > %llu",
 805                                 k->k->version.lo,
 806                                 atomic64_read(&c->key_version)))
 807                         atomic64_set(&c->key_version, k->k->version.lo);
 808         }
 809
 810         ret = commit_do(trans, NULL, NULL, 0,
 811                         bch2_mark_key(trans, btree_id, level, old, *k, flags));
 812 fsck_err:
 813 err:
 814         if (ret)
 815                 bch_err(c, "error from %s(): %s", __func__, bch2_err_str(ret));
 816         return ret;
 817 }
 818
 819 static int btree_gc_mark_node(struct btree_trans *trans, struct btree *b, bool initial)
 820 {
 821         struct bch_fs *c = trans->c;
 822         struct btree_node_iter iter;
 823         struct bkey unpacked;
 824         struct bkey_s_c k;
 825         struct bkey_buf prev, cur;
 826         int ret = 0;
 827
 828         if (!btree_node_type_needs_gc(btree_node_type(b)))
 829                 return 0;
 830
 831         bch2_btree_node_iter_init_from_start(&iter, b);
 832         bch2_bkey_buf_init(&prev);
 833         bch2_bkey_buf_init(&cur);
 834         bkey_init(&prev.k->k);
 835
 836         while ((k = bch2_btree_node_iter_peek_unpack(&iter, b, &unpacked)).k) {
 837                 ret = bch2_gc_mark_key(trans, b->c.btree_id, b->c.level, false,
 838                                        &k, initial);
 839                 if (ret)
 840                         break;
 841
 842                 bch2_btree_node_iter_advance(&iter, b);
 843
 844                 if (b->c.level) {
 845                         bch2_bkey_buf_reassemble(&cur, c, k);
 846
 847                         ret = bch2_gc_check_topology(c, b, &prev, cur,
 848                                         bch2_btree_node_iter_end(&iter));
 849                         if (ret)
 850                                 break;
 851                 }
 852         }
 853
 854         bch2_bkey_buf_exit(&cur, c);
 855         bch2_bkey_buf_exit(&prev, c);
 856         return ret;
 857 }
 858
 859 static int bch2_gc_btree(struct btree_trans *trans, enum btree_id btree_id,
 860                          bool initial, bool metadata_only)
 861 {
 862         struct bch_fs *c = trans->c;
 863         struct btree_iter iter;
 864         struct btree *b;
 865         unsigned depth = metadata_only ? 1 : 0;
 866         int ret = 0;
 867
 868         gc_pos_set(c, gc_pos_btree(btree_id, POS_MIN, 0));
 869
 870         __for_each_btree_node(trans, iter, btree_id, POS_MIN,
 871                               0, depth, BTREE_ITER_PREFETCH, b, ret) {
 872                 bch2_verify_btree_nr_keys(b);
 873
 874                 gc_pos_set(c, gc_pos_btree_node(b));
 875
 876                 ret = btree_gc_mark_node(trans, b, initial);
 877                 if (ret)
 878                         break;
 879         }
 880         bch2_trans_iter_exit(trans, &iter);
 881
 882         if (ret)
 883                 return ret;
 884
 885         mutex_lock(&c->btree_root_lock);
 886         b = c->btree_roots[btree_id].b;
 887         if (!btree_node_fake(b)) {
 888                 struct bkey_s_c k = bkey_i_to_s_c(&b->key);
 889
 890                 ret = bch2_gc_mark_key(trans, b->c.btree_id, b->c.level + 1,
 891                                        true, &k, initial);
 892         }
 893         gc_pos_set(c, gc_pos_btree_root(b->c.btree_id));
 894         mutex_unlock(&c->btree_root_lock);
 895
 896         return ret;
 897 }
 898
 899 static int bch2_gc_btree_init_recurse(struct btree_trans *trans, struct btree *b,
 900                                       unsigned target_depth)
 901 {
 902         struct bch_fs *c = trans->c;
 903         struct btree_and_journal_iter iter;
 904         struct bkey_s_c k;
 905         struct bkey_buf cur, prev;
 906         struct printbuf buf = PRINTBUF;
 907         int ret = 0;
 908
 909         bch2_btree_and_journal_iter_init_node_iter(&iter, c, b);
 910         bch2_bkey_buf_init(&prev);
 911         bch2_bkey_buf_init(&cur);
 912         bkey_init(&prev.k->k);
 913
 914         while ((k = bch2_btree_and_journal_iter_peek(&iter)).k) {
 915                 BUG_ON(bpos_lt(k.k->p, b->data->min_key));
 916                 BUG_ON(bpos_gt(k.k->p, b->data->max_key));
 917
 918                 ret = bch2_gc_mark_key(trans, b->c.btree_id, b->c.level,
 919                                        false, &k, true);
 920                 if (ret) {
 921                         bch_err(c, "%s: error from bch2_gc_mark_key: %s",
 922                                 __func__, bch2_err_str(ret));
 923                         goto fsck_err;
 924                 }
 925
 926                 if (b->c.level) {
 927                         bch2_bkey_buf_reassemble(&cur, c, k);
 928                         k = bkey_i_to_s_c(cur.k);
 929
 930                         bch2_btree_and_journal_iter_advance(&iter);
 931
 932                         ret = bch2_gc_check_topology(c, b,
 933                                         &prev, cur,
 934                                         !bch2_btree_and_journal_iter_peek(&iter).k);
 935                         if (ret)
 936                                 goto fsck_err;
 937                 } else {
 938                         bch2_btree_and_journal_iter_advance(&iter);
 939                 }
 940         }
 941
 942         if (b->c.level > target_depth) {
 943                 bch2_btree_and_journal_iter_exit(&iter);
 944                 bch2_btree_and_journal_iter_init_node_iter(&iter, c, b);
 945
 946                 while ((k = bch2_btree_and_journal_iter_peek(&iter)).k) {
 947                         struct btree *child;
 948
 949                         bch2_bkey_buf_reassemble(&cur, c, k);
 950                         bch2_btree_and_journal_iter_advance(&iter);
 951
 952                         child = bch2_btree_node_get_noiter(trans, cur.k,
 953                                                 b->c.btree_id, b->c.level - 1,
 954                                                 false);
 955                         ret = PTR_ERR_OR_ZERO(child);
 956
 957                         if (ret == -EIO) {
 958                                 bch2_topology_error(c);
 959
 960                                 if (__fsck_err(c,
 961                                           FSCK_CAN_FIX|
 962                                           FSCK_CAN_IGNORE|
 963                                           FSCK_NO_RATELIMIT,
 964                                           "Unreadable btree node at btree %s level %u:\n"
 965                                           "  %s",
 966                                           bch2_btree_ids[b->c.btree_id],
 967                                           b->c.level - 1,
 968                                           (printbuf_reset(&buf),
 969                                            bch2_bkey_val_to_text(&buf, c, bkey_i_to_s_c(cur.k)), buf.buf)) &&
 970                                     !test_bit(BCH_FS_TOPOLOGY_REPAIR_DONE, &c->flags)) {
 971                                         ret = -BCH_ERR_need_topology_repair;
 972                                         bch_info(c, "Halting mark and sweep to start topology repair pass");
 973                                         goto fsck_err;
 974                                 } else {
 975                                         /* Continue marking when opted to not
 976                                          * fix the error: */
 977                                         ret = 0;
 978                                         set_bit(BCH_FS_INITIAL_GC_UNFIXED, &c->flags);
 979                                         continue;
 980                                 }
 981                         } else if (ret) {
 982                                 bch_err(c, "%s: error getting btree node: %s",
 983                                         __func__, bch2_err_str(ret));
 984                                 break;
 985                         }
 986
 987                         ret = bch2_gc_btree_init_recurse(trans, child,
 988                                                          target_depth);
 989                         six_unlock_read(&child->c.lock);
 990
 991                         if (ret)
 992                                 break;
 993                 }
 994         }
 995 fsck_err:
 996         bch2_bkey_buf_exit(&cur, c);
 997         bch2_bkey_buf_exit(&prev, c);
 998         bch2_btree_and_journal_iter_exit(&iter);
 999         printbuf_exit(&buf);
1000         return ret;
1001 }
1002
1003 static int bch2_gc_btree_init(struct btree_trans *trans,
1004                               enum btree_id btree_id,
1005                               bool metadata_only)
1006 {
1007         struct bch_fs *c = trans->c;
1008         struct btree *b;
1009         unsigned target_depth = metadata_only ? 1 : 0;
1010         struct printbuf buf = PRINTBUF;
1011         int ret = 0;
1012
1013         b = c->btree_roots[btree_id].b;
1014
1015         if (btree_node_fake(b))
1016                 return 0;
1017
1018         six_lock_read(&b->c.lock, NULL, NULL);
1019         printbuf_reset(&buf);
1020         bch2_bpos_to_text(&buf, b->data->min_key);
1021         if (mustfix_fsck_err_on(!bpos_eq(b->data->min_key, POS_MIN), c,
1022                         "btree root with incorrect min_key: %s", buf.buf)) {
1023                 bch_err(c, "repair unimplemented");
1024                 ret = -BCH_ERR_fsck_repair_unimplemented;
1025                 goto fsck_err;
1026         }
1027
1028         printbuf_reset(&buf);
1029         bch2_bpos_to_text(&buf, b->data->max_key);
1030         if (mustfix_fsck_err_on(!bpos_eq(b->data->max_key, SPOS_MAX), c,
1031                         "btree root with incorrect max_key: %s", buf.buf)) {
1032                 bch_err(c, "repair unimplemented");
1033                 ret = -BCH_ERR_fsck_repair_unimplemented;
1034                 goto fsck_err;
1035         }
1036
1037         if (b->c.level >= target_depth)
1038                 ret = bch2_gc_btree_init_recurse(trans, b, target_depth);
1039
1040         if (!ret) {
1041                 struct bkey_s_c k = bkey_i_to_s_c(&b->key);
1042
1043                 ret = bch2_gc_mark_key(trans, b->c.btree_id, b->c.level + 1, true,
1044                                        &k, true);
1045         }
1046 fsck_err:
1047         six_unlock_read(&b->c.lock);
1048
1049         if (ret < 0)
1050                 bch_err(c, "error from %s(): %s", __func__, bch2_err_str(ret));
1051         printbuf_exit(&buf);
1052         return ret;
1053 }
1054
1055 static inline int btree_id_gc_phase_cmp(enum btree_id l, enum btree_id r)
1056 {
1057         return  (int) btree_id_to_gc_phase(l) -
1058                 (int) btree_id_to_gc_phase(r);
1059 }
1060
1061 static int bch2_gc_btrees(struct bch_fs *c, bool initial, bool metadata_only)
1062 {
1063         struct btree_trans trans;
1064         enum btree_id ids[BTREE_ID_NR];
1065         unsigned i;
1066         int ret = 0;
1067
1068         bch2_trans_init(&trans, c, 0, 0);
1069
1070         if (initial)
1071                 trans.is_initial_gc = true;
1072
1073         for (i = 0; i < BTREE_ID_NR; i++)
1074                 ids[i] = i;
1075         bubble_sort(ids, BTREE_ID_NR, btree_id_gc_phase_cmp);
1076
1077         for (i = 0; i < BTREE_ID_NR && !ret; i++)
1078                 ret = initial
1079                         ? bch2_gc_btree_init(&trans, ids[i], metadata_only)
1080                         : bch2_gc_btree(&trans, ids[i], initial, metadata_only);
1081
1082         if (ret < 0)
1083                 bch_err(c, "error from %s(): %s", __func__, bch2_err_str(ret));
1084
1085         bch2_trans_exit(&trans);
1086         return ret;
1087 }
1088
1089 static void mark_metadata_sectors(struct bch_fs *c, struct bch_dev *ca,
1090                                   u64 start, u64 end,
1091                                   enum bch_data_type type,
1092                                   unsigned flags)
1093 {
1094         u64 b = sector_to_bucket(ca, start);
1095
1096         do {
1097                 unsigned sectors =
1098                         min_t(u64, bucket_to_sector(ca, b + 1), end) - start;
1099
1100                 bch2_mark_metadata_bucket(c, ca, b, type, sectors,
1101                                           gc_phase(GC_PHASE_SB), flags);
1102                 b++;
1103                 start += sectors;
1104         } while (start < end);
1105 }
1106
1107 static void bch2_mark_dev_superblock(struct bch_fs *c, struct bch_dev *ca,
1108                                      unsigned flags)
1109 {
1110         struct bch_sb_layout *layout = &ca->disk_sb.sb->layout;
1111         unsigned i;
1112         u64 b;
1113
1114         for (i = 0; i < layout->nr_superblocks; i++) {
1115                 u64 offset = le64_to_cpu(layout->sb_offset[i]);
1116
1117                 if (offset == BCH_SB_SECTOR)
1118                         mark_metadata_sectors(c, ca, 0, BCH_SB_SECTOR,
1119                                               BCH_DATA_sb, flags);
1120
1121                 mark_metadata_sectors(c, ca, offset,
1122                                       offset + (1 << layout->sb_max_size_bits),
1123                                       BCH_DATA_sb, flags);
1124         }
1125
1126         for (i = 0; i < ca->journal.nr; i++) {
1127                 b = ca->journal.buckets[i];
1128                 bch2_mark_metadata_bucket(c, ca, b, BCH_DATA_journal,
1129                                           ca->mi.bucket_size,
1130                                           gc_phase(GC_PHASE_SB), flags);
1131         }
1132 }
1133
1134 static void bch2_mark_superblocks(struct bch_fs *c)
1135 {
1136         struct bch_dev *ca;
1137         unsigned i;
1138
1139         mutex_lock(&c->sb_lock);
1140         gc_pos_set(c, gc_phase(GC_PHASE_SB));
1141
1142         for_each_online_member(ca, c, i)
1143                 bch2_mark_dev_superblock(c, ca, BTREE_TRIGGER_GC);
1144         mutex_unlock(&c->sb_lock);
1145 }
1146
1147 #if 0
1148 /* Also see bch2_pending_btree_node_free_insert_done() */
1149 static void bch2_mark_pending_btree_node_frees(struct bch_fs *c)
1150 {
1151         struct btree_update *as;
1152         struct pending_btree_node_free *d;
1153
1154         mutex_lock(&c->btree_interior_update_lock);
1155         gc_pos_set(c, gc_phase(GC_PHASE_PENDING_DELETE));
1156
1157         for_each_pending_btree_node_free(c, as, d)
1158                 if (d->index_update_done)
1159                         bch2_mark_key(c, bkey_i_to_s_c(&d->key), BTREE_TRIGGER_GC);
1160
1161         mutex_unlock(&c->btree_interior_update_lock);
1162 }
1163 #endif
1164
1165 static void bch2_gc_free(struct bch_fs *c)
1166 {
1167         struct bch_dev *ca;
1168         unsigned i;
1169
1170         genradix_free(&c->reflink_gc_table);
1171         genradix_free(&c->gc_stripes);
1172
1173         for_each_member_device(ca, c, i) {
1174                 kvpfree(rcu_dereference_protected(ca->buckets_gc, 1),
1175                         sizeof(struct bucket_array) +
1176                         ca->mi.nbuckets * sizeof(struct bucket));
1177                 ca->buckets_gc = NULL;
1178
1179                 free_percpu(ca->usage_gc);
1180                 ca->usage_gc = NULL;
1181         }
1182
1183         free_percpu(c->usage_gc);
1184         c->usage_gc = NULL;
1185 }
1186
1187 static int bch2_gc_done(struct bch_fs *c,
1188                         bool initial, bool metadata_only)
1189 {
1190         struct bch_dev *ca = NULL;
1191         struct printbuf buf = PRINTBUF;
1192         bool verify = !metadata_only &&
1193                 !c->opts.reconstruct_alloc &&
1194                 (!initial || (c->sb.compat & (1ULL << BCH_COMPAT_alloc_info)));
1195         unsigned i, dev;
1196         int ret = 0;
1197
1198         percpu_down_write(&c->mark_lock);
1199
1200 #define copy_field(_f, _msg, ...)                                       \
1201         if (dst->_f != src->_f &&                                       \
1202             (!verify ||                                                 \
1203              fsck_err(c, _msg ": got %llu, should be %llu"              \
1204                       , ##__VA_ARGS__, dst->_f, src->_f)))              \
1205                 dst->_f = src->_f
1206 #define copy_stripe_field(_f, _msg, ...)                                \
1207         if (dst->_f != src->_f &&                                       \
1208             (!verify ||                                                 \
1209              fsck_err(c, "stripe %zu has wrong "_msg                    \
1210                       ": got %u, should be %u",                         \
1211                       iter.pos, ##__VA_ARGS__,                          \
1212                       dst->_f, src->_f)))                               \
1213                 dst->_f = src->_f
1214 #define copy_dev_field(_f, _msg, ...)                                   \
1215         copy_field(_f, "dev %u has wrong " _msg, dev, ##__VA_ARGS__)
1216 #define copy_fs_field(_f, _msg, ...)                                    \
1217         copy_field(_f, "fs has wrong " _msg, ##__VA_ARGS__)
1218
1219         for (i = 0; i < ARRAY_SIZE(c->usage); i++)
1220                 bch2_fs_usage_acc_to_base(c, i);
1221
1222         for_each_member_device(ca, c, dev) {
1223                 struct bch_dev_usage *dst = ca->usage_base;
1224                 struct bch_dev_usage *src = (void *)
1225                         bch2_acc_percpu_u64s((void *) ca->usage_gc,
1226                                              dev_usage_u64s());
1227
1228                 copy_dev_field(buckets_ec,              "buckets_ec");
1229
1230                 for (i = 0; i < BCH_DATA_NR; i++) {
1231                         copy_dev_field(d[i].buckets,    "%s buckets", bch2_data_types[i]);
1232                         copy_dev_field(d[i].sectors,    "%s sectors", bch2_data_types[i]);
1233                         copy_dev_field(d[i].fragmented, "%s fragmented", bch2_data_types[i]);
1234                 }
1235         };
1236
1237         {
1238                 unsigned nr = fs_usage_u64s(c);
1239                 struct bch_fs_usage *dst = c->usage_base;
1240                 struct bch_fs_usage *src = (void *)
1241                         bch2_acc_percpu_u64s((void *) c->usage_gc, nr);
1242
1243                 copy_fs_field(hidden,           "hidden");
1244                 copy_fs_field(btree,            "btree");
1245
1246                 if (!metadata_only) {
1247                         copy_fs_field(data,     "data");
1248                         copy_fs_field(cached,   "cached");
1249                         copy_fs_field(reserved, "reserved");
1250                         copy_fs_field(nr_inodes,"nr_inodes");
1251
1252                         for (i = 0; i < BCH_REPLICAS_MAX; i++)
1253                                 copy_fs_field(persistent_reserved[i],
1254                                               "persistent_reserved[%i]", i);
1255                 }
1256
1257                 for (i = 0; i < c->replicas.nr; i++) {
1258                         struct bch_replicas_entry *e =
1259                                 cpu_replicas_entry(&c->replicas, i);
1260
1261                         if (metadata_only &&
1262                             (e->data_type == BCH_DATA_user ||
1263                              e->data_type == BCH_DATA_cached))
1264                                 continue;
1265
1266                         printbuf_reset(&buf);
1267                         bch2_replicas_entry_to_text(&buf, e);
1268
1269                         copy_fs_field(replicas[i], "%s", buf.buf);
1270                 }
1271         }
1272
1273 #undef copy_fs_field
1274 #undef copy_dev_field
1275 #undef copy_stripe_field
1276 #undef copy_field
1277 fsck_err:
1278         if (ca)
1279                 percpu_ref_put(&ca->ref);
1280         if (ret)
1281                 bch_err(c, "error from %s(): %s", __func__, bch2_err_str(ret));
1282
1283         percpu_up_write(&c->mark_lock);
1284         printbuf_exit(&buf);
1285         return ret;
1286 }
1287
1288 static int bch2_gc_start(struct bch_fs *c)
1289 {
1290         struct bch_dev *ca = NULL;
1291         unsigned i;
1292
1293         BUG_ON(c->usage_gc);
1294
1295         c->usage_gc = __alloc_percpu_gfp(fs_usage_u64s(c) * sizeof(u64),
1296                                          sizeof(u64), GFP_KERNEL);
1297         if (!c->usage_gc) {
1298                 bch_err(c, "error allocating c->usage_gc");
1299                 return -BCH_ERR_ENOMEM_gc_start;
1300         }
1301
1302         for_each_member_device(ca, c, i) {
1303                 BUG_ON(ca->usage_gc);
1304
1305                 ca->usage_gc = alloc_percpu(struct bch_dev_usage);
1306                 if (!ca->usage_gc) {
1307                         bch_err(c, "error allocating ca->usage_gc");
1308                         percpu_ref_put(&ca->ref);
1309                         return -BCH_ERR_ENOMEM_gc_start;
1310                 }
1311
1312                 this_cpu_write(ca->usage_gc->d[BCH_DATA_free].buckets,
1313                                ca->mi.nbuckets - ca->mi.first_bucket);
1314         }
1315
1316         return 0;
1317 }
1318
1319 static int bch2_gc_reset(struct bch_fs *c)
1320 {
1321         struct bch_dev *ca;
1322         unsigned i;
1323
1324         for_each_member_device(ca, c, i) {
1325                 free_percpu(ca->usage_gc);
1326                 ca->usage_gc = NULL;
1327         }
1328
1329         free_percpu(c->usage_gc);
1330         c->usage_gc = NULL;
1331
1332         return bch2_gc_start(c);
1333 }
1334
1335 /* returns true if not equal */
1336 static inline bool bch2_alloc_v4_cmp(struct bch_alloc_v4 l,
1337                                      struct bch_alloc_v4 r)
1338 {
1339         return  l.gen != r.gen                          ||
1340                 l.oldest_gen != r.oldest_gen            ||
1341                 l.data_type != r.data_type              ||
1342                 l.dirty_sectors != r.dirty_sectors      ||
1343                 l.cached_sectors != r.cached_sectors     ||
1344                 l.stripe_redundancy != r.stripe_redundancy ||
1345                 l.stripe != r.stripe;
1346 }
1347
1348 static int bch2_alloc_write_key(struct btree_trans *trans,
1349                                 struct btree_iter *iter,
1350                                 struct bkey_s_c k,
1351                                 bool metadata_only)
1352 {
1353         struct bch_fs *c = trans->c;
1354         struct bch_dev *ca = bch_dev_bkey_exists(c, iter->pos.inode);
1355         struct bucket gc, *b;
1356         struct bkey_i_alloc_v4 *a;
1357         struct bch_alloc_v4 old_convert, new;
1358         const struct bch_alloc_v4 *old;
1359         enum bch_data_type type;
1360         int ret;
1361
1362         if (bkey_ge(iter->pos, POS(ca->dev_idx, ca->mi.nbuckets)))
1363                 return 1;
1364
1365         old = bch2_alloc_to_v4(k, &old_convert);
1366         new = *old;
1367
1368         percpu_down_read(&c->mark_lock);
1369         b = gc_bucket(ca, iter->pos.offset);
1370
1371         /*
1372          * b->data_type doesn't yet include need_discard & need_gc_gen states -
1373          * fix that here:
1374          */
1375         type = __alloc_data_type(b->dirty_sectors,
1376                                  b->cached_sectors,
1377                                  b->stripe,
1378                                  *old,
1379                                  b->data_type);
1380         if (b->data_type != type) {
1381                 struct bch_dev_usage *u;
1382
1383                 preempt_disable();
1384                 u = this_cpu_ptr(ca->usage_gc);
1385                 u->d[b->data_type].buckets--;
1386                 b->data_type = type;
1387                 u->d[b->data_type].buckets++;
1388                 preempt_enable();
1389         }
1390
1391         gc = *b;
1392         percpu_up_read(&c->mark_lock);
1393
1394         if (metadata_only &&
1395             gc.data_type != BCH_DATA_sb &&
1396             gc.data_type != BCH_DATA_journal &&
1397             gc.data_type != BCH_DATA_btree)
1398                 return 0;
1399
1400         if (gen_after(old->gen, gc.gen))
1401                 return 0;
1402
1403         if (c->opts.reconstruct_alloc ||
1404             fsck_err_on(new.data_type != gc.data_type, c,
1405                         "bucket %llu:%llu gen %u has wrong data_type"
1406                         ": got %s, should be %s",
1407                         iter->pos.inode, iter->pos.offset,
1408                         gc.gen,
1409                         bch2_data_types[new.data_type],
1410                         bch2_data_types[gc.data_type]))
1411                 new.data_type = gc.data_type;
1412
1413 #define copy_bucket_field(_f)                                           \
1414         if (c->opts.reconstruct_alloc ||                                \
1415             fsck_err_on(new._f != gc._f, c,                             \
1416                         "bucket %llu:%llu gen %u data type %s has wrong " #_f   \
1417                         ": got %u, should be %u",                       \
1418                         iter->pos.inode, iter->pos.offset,              \
1419                         gc.gen,                                         \
1420                         bch2_data_types[gc.data_type],                  \
1421                         new._f, gc._f))                                 \
1422                 new._f = gc._f;                                         \
1423
1424         copy_bucket_field(gen);
1425         copy_bucket_field(dirty_sectors);
1426         copy_bucket_field(cached_sectors);
1427         copy_bucket_field(stripe_redundancy);
1428         copy_bucket_field(stripe);
1429 #undef copy_bucket_field
1430
1431         if (!bch2_alloc_v4_cmp(*old, new))
1432                 return 0;
1433
1434         a = bch2_alloc_to_v4_mut(trans, k);
1435         ret = PTR_ERR_OR_ZERO(a);
1436         if (ret)
1437                 return ret;
1438
1439         a->v = new;
1440
1441         /*
1442          * The trigger normally makes sure this is set, but we're not running
1443          * triggers:
1444          */
1445         if (a->v.data_type == BCH_DATA_cached && !a->v.io_time[READ])
1446                 a->v.io_time[READ] = max_t(u64, 1, atomic64_read(&c->io_clock[READ].now));
1447
1448         ret = bch2_trans_update(trans, iter, &a->k_i, BTREE_TRIGGER_NORUN);
1449 fsck_err:
1450         return ret;
1451 }
1452
1453 static int bch2_gc_alloc_done(struct bch_fs *c, bool metadata_only)
1454 {
1455         struct btree_trans trans;
1456         struct btree_iter iter;
1457         struct bkey_s_c k;
1458         struct bch_dev *ca;
1459         unsigned i;
1460         int ret = 0;
1461
1462         bch2_trans_init(&trans, c, 0, 0);
1463
1464         for_each_member_device(ca, c, i) {
1465                 ret = for_each_btree_key_commit(&trans, iter, BTREE_ID_alloc,
1466                                 POS(ca->dev_idx, ca->mi.first_bucket),
1467                                 BTREE_ITER_SLOTS|BTREE_ITER_PREFETCH, k,
1468                                 NULL, NULL, BTREE_INSERT_LAZY_RW,
1469                         bch2_alloc_write_key(&trans, &iter, k, metadata_only));
1470
1471                 if (ret < 0) {
1472                         bch_err(c, "error writing alloc info: %s", bch2_err_str(ret));
1473                         percpu_ref_put(&ca->ref);
1474                         break;
1475                 }
1476         }
1477
1478         bch2_trans_exit(&trans);
1479         return ret < 0 ? ret : 0;
1480 }
1481
1482 static int bch2_gc_alloc_start(struct bch_fs *c, bool metadata_only)
1483 {
1484         struct bch_dev *ca;
1485         struct btree_trans trans;
1486         struct btree_iter iter;
1487         struct bkey_s_c k;
1488         struct bucket *g;
1489         struct bch_alloc_v4 a_convert;
1490         const struct bch_alloc_v4 *a;
1491         unsigned i;
1492         int ret;
1493
1494         for_each_member_device(ca, c, i) {
1495                 struct bucket_array *buckets = kvpmalloc(sizeof(struct bucket_array) +
1496                                 ca->mi.nbuckets * sizeof(struct bucket),
1497                                 GFP_KERNEL|__GFP_ZERO);
1498                 if (!buckets) {
1499                         percpu_ref_put(&ca->ref);
1500                         bch_err(c, "error allocating ca->buckets[gc]");
1501                         return -BCH_ERR_ENOMEM_gc_alloc_start;
1502                 }
1503
1504                 buckets->first_bucket   = ca->mi.first_bucket;
1505                 buckets->nbuckets       = ca->mi.nbuckets;
1506                 rcu_assign_pointer(ca->buckets_gc, buckets);
1507         };
1508
1509         bch2_trans_init(&trans, c, 0, 0);
1510
1511         for_each_btree_key(&trans, iter, BTREE_ID_alloc, POS_MIN,
1512                            BTREE_ITER_PREFETCH, k, ret) {
1513                 ca = bch_dev_bkey_exists(c, k.k->p.inode);
1514                 g = gc_bucket(ca, k.k->p.offset);
1515
1516                 a = bch2_alloc_to_v4(k, &a_convert);
1517
1518                 g->gen_valid    = 1;
1519                 g->gen          = a->gen;
1520
1521                 if (metadata_only &&
1522                     (a->data_type == BCH_DATA_user ||
1523                      a->data_type == BCH_DATA_cached ||
1524                      a->data_type == BCH_DATA_parity)) {
1525                         g->data_type            = a->data_type;
1526                         g->dirty_sectors        = a->dirty_sectors;
1527                         g->cached_sectors       = a->cached_sectors;
1528                         g->stripe               = a->stripe;
1529                         g->stripe_redundancy    = a->stripe_redundancy;
1530                 }
1531         }
1532         bch2_trans_iter_exit(&trans, &iter);
1533
1534         bch2_trans_exit(&trans);
1535
1536         if (ret)
1537                 bch_err(c, "error reading alloc info at gc start: %s", bch2_err_str(ret));
1538
1539         return ret;
1540 }
1541
1542 static void bch2_gc_alloc_reset(struct bch_fs *c, bool metadata_only)
1543 {
1544         struct bch_dev *ca;
1545         unsigned i;
1546
1547         for_each_member_device(ca, c, i) {
1548                 struct bucket_array *buckets = gc_bucket_array(ca);
1549                 struct bucket *g;
1550
1551                 for_each_bucket(g, buckets) {
1552                         if (metadata_only &&
1553                             (g->data_type == BCH_DATA_user ||
1554                              g->data_type == BCH_DATA_cached ||
1555                              g->data_type == BCH_DATA_parity))
1556                                 continue;
1557                         g->data_type = 0;
1558                         g->dirty_sectors = 0;
1559                         g->cached_sectors = 0;
1560                 }
1561         };
1562 }
1563
1564 static int bch2_gc_write_reflink_key(struct btree_trans *trans,
1565                                      struct btree_iter *iter,
1566                                      struct bkey_s_c k,
1567                                      size_t *idx)
1568 {
1569         struct bch_fs *c = trans->c;
1570         const __le64 *refcount = bkey_refcount_c(k);
1571         struct printbuf buf = PRINTBUF;
1572         struct reflink_gc *r;
1573         int ret = 0;
1574
1575         if (!refcount)
1576                 return 0;
1577
1578         while ((r = genradix_ptr(&c->reflink_gc_table, *idx)) &&
1579                r->offset < k.k->p.offset)
1580                 ++*idx;
1581
1582         if (!r ||
1583             r->offset != k.k->p.offset ||
1584             r->size != k.k->size) {
1585                 bch_err(c, "unexpected inconsistency walking reflink table at gc finish");
1586                 return -EINVAL;
1587         }
1588
1589         if (fsck_err_on(r->refcount != le64_to_cpu(*refcount), c,
1590                         "reflink key has wrong refcount:\n"
1591                         "  %s\n"
1592                         "  should be %u",
1593                         (bch2_bkey_val_to_text(&buf, c, k), buf.buf),
1594                         r->refcount)) {
1595                 struct bkey_i *new = bch2_bkey_make_mut(trans, k);
1596
1597                 ret = PTR_ERR_OR_ZERO(new);
1598                 if (ret)
1599                         return ret;
1600
1601                 if (!r->refcount)
1602                         new->k.type = KEY_TYPE_deleted;
1603                 else
1604                         *bkey_refcount(new) = cpu_to_le64(r->refcount);
1605
1606                 ret = bch2_trans_update(trans, iter, new, 0);
1607         }
1608 fsck_err:
1609         printbuf_exit(&buf);
1610         return ret;
1611 }
1612
1613 static int bch2_gc_reflink_done(struct bch_fs *c, bool metadata_only)
1614 {
1615         struct btree_trans trans;
1616         struct btree_iter iter;
1617         struct bkey_s_c k;
1618         size_t idx = 0;
1619         int ret = 0;
1620
1621         if (metadata_only)
1622                 return 0;
1623
1624         bch2_trans_init(&trans, c, 0, 0);
1625
1626         ret = for_each_btree_key_commit(&trans, iter,
1627                         BTREE_ID_reflink, POS_MIN,
1628                         BTREE_ITER_PREFETCH, k,
1629                         NULL, NULL, BTREE_INSERT_NOFAIL,
1630                 bch2_gc_write_reflink_key(&trans, &iter, k, &idx));
1631
1632         c->reflink_gc_nr = 0;
1633         bch2_trans_exit(&trans);
1634         return ret;
1635 }
1636
1637 static int bch2_gc_reflink_start(struct bch_fs *c,
1638                                  bool metadata_only)
1639 {
1640         struct btree_trans trans;
1641         struct btree_iter iter;
1642         struct bkey_s_c k;
1643         struct reflink_gc *r;
1644         int ret = 0;
1645
1646         if (metadata_only)
1647                 return 0;
1648
1649         bch2_trans_init(&trans, c, 0, 0);
1650         c->reflink_gc_nr = 0;
1651
1652         for_each_btree_key(&trans, iter, BTREE_ID_reflink, POS_MIN,
1653                            BTREE_ITER_PREFETCH, k, ret) {
1654                 const __le64 *refcount = bkey_refcount_c(k);
1655
1656                 if (!refcount)
1657                         continue;
1658
1659                 r = genradix_ptr_alloc(&c->reflink_gc_table, c->reflink_gc_nr++,
1660                                        GFP_KERNEL);
1661                 if (!r) {
1662                         ret = -BCH_ERR_ENOMEM_gc_reflink_start;
1663                         break;
1664                 }
1665
1666                 r->offset       = k.k->p.offset;
1667                 r->size         = k.k->size;
1668                 r->refcount     = 0;
1669         }
1670         bch2_trans_iter_exit(&trans, &iter);
1671
1672         bch2_trans_exit(&trans);
1673         return ret;
1674 }
1675
1676 static void bch2_gc_reflink_reset(struct bch_fs *c, bool metadata_only)
1677 {
1678         struct genradix_iter iter;
1679         struct reflink_gc *r;
1680
1681         genradix_for_each(&c->reflink_gc_table, iter, r)
1682                 r->refcount = 0;
1683 }
1684
1685 static int bch2_gc_write_stripes_key(struct btree_trans *trans,
1686                                      struct btree_iter *iter,
1687                                      struct bkey_s_c k)
1688 {
1689         struct bch_fs *c = trans->c;
1690         struct printbuf buf = PRINTBUF;
1691         const struct bch_stripe *s;
1692         struct gc_stripe *m;
1693         bool bad = false;
1694         unsigned i;
1695         int ret = 0;
1696
1697         if (k.k->type != KEY_TYPE_stripe)
1698                 return 0;
1699
1700         s = bkey_s_c_to_stripe(k).v;
1701         m = genradix_ptr(&c->gc_stripes, k.k->p.offset);
1702
1703         for (i = 0; i < s->nr_blocks; i++) {
1704                 u32 old = stripe_blockcount_get(s, i);
1705                 u32 new = (m ? m->block_sectors[i] : 0);
1706
1707                 if (old != new) {
1708                         prt_printf(&buf, "stripe block %u has wrong sector count: got %u, should be %u\n",
1709                                    i, old, new);
1710                         bad = true;
1711                 }
1712         }
1713
1714         if (bad)
1715                 bch2_bkey_val_to_text(&buf, c, k);
1716
1717         if (fsck_err_on(bad, c, "%s", buf.buf)) {
1718                 struct bkey_i_stripe *new;
1719
1720                 new = bch2_trans_kmalloc(trans, bkey_bytes(k.k));
1721                 ret = PTR_ERR_OR_ZERO(new);
1722                 if (ret)
1723                         return ret;
1724
1725                 bkey_reassemble(&new->k_i, k);
1726
1727                 for (i = 0; i < new->v.nr_blocks; i++)
1728                         stripe_blockcount_set(&new->v, i, m ? m->block_sectors[i] : 0);
1729
1730                 ret = bch2_trans_update(trans, iter, &new->k_i, 0);
1731         }
1732 fsck_err:
1733         printbuf_exit(&buf);
1734         return ret;
1735 }
1736
1737 static int bch2_gc_stripes_done(struct bch_fs *c, bool metadata_only)
1738 {
1739         struct btree_trans trans;
1740         struct btree_iter iter;
1741         struct bkey_s_c k;
1742         int ret = 0;
1743
1744         if (metadata_only)
1745                 return 0;
1746
1747         bch2_trans_init(&trans, c, 0, 0);
1748
1749         ret = for_each_btree_key_commit(&trans, iter,
1750                         BTREE_ID_stripes, POS_MIN,
1751                         BTREE_ITER_PREFETCH, k,
1752                         NULL, NULL, BTREE_INSERT_NOFAIL,
1753                 bch2_gc_write_stripes_key(&trans, &iter, k));
1754
1755         bch2_trans_exit(&trans);
1756         return ret;
1757 }
1758
1759 static void bch2_gc_stripes_reset(struct bch_fs *c, bool metadata_only)
1760 {
1761         genradix_free(&c->gc_stripes);
1762 }
1763
1764 /**
1765  * bch2_gc - walk _all_ references to buckets, and recompute them:
1766  *
1767  * Order matters here:
1768  *  - Concurrent GC relies on the fact that we have a total ordering for
1769  *    everything that GC walks - see  gc_will_visit_node(),
1770  *    gc_will_visit_root()
1771  *
1772  *  - also, references move around in the course of index updates and
1773  *    various other crap: everything needs to agree on the ordering
1774  *    references are allowed to move around in - e.g., we're allowed to
1775  *    start with a reference owned by an open_bucket (the allocator) and
1776  *    move it to the btree, but not the reverse.
1777  *
1778  *    This is necessary to ensure that gc doesn't miss references that
1779  *    move around - if references move backwards in the ordering GC
1780  *    uses, GC could skip past them
1781  */
1782 int bch2_gc(struct bch_fs *c, bool initial, bool metadata_only)
1783 {
1784         unsigned iter = 0;
1785         int ret;
1786
1787         lockdep_assert_held(&c->state_lock);
1788
1789         down_write(&c->gc_lock);
1790
1791         bch2_btree_interior_updates_flush(c);
1792
1793         ret   = bch2_gc_start(c) ?:
1794                 bch2_gc_alloc_start(c, metadata_only) ?:
1795                 bch2_gc_reflink_start(c, metadata_only);
1796         if (ret)
1797                 goto out;
1798 again:
1799         gc_pos_set(c, gc_phase(GC_PHASE_START));
1800
1801         bch2_mark_superblocks(c);
1802
1803         if (BCH_SB_HAS_TOPOLOGY_ERRORS(c->disk_sb.sb) &&
1804             !test_bit(BCH_FS_INITIAL_GC_DONE, &c->flags) &&
1805             c->opts.fix_errors != FSCK_OPT_NO) {
1806                 bch_info(c, "Starting topology repair pass");
1807                 ret = bch2_repair_topology(c);
1808                 if (ret)
1809                         goto out;
1810                 bch_info(c, "Topology repair pass done");
1811
1812                 set_bit(BCH_FS_TOPOLOGY_REPAIR_DONE, &c->flags);
1813         }
1814
1815         ret = bch2_gc_btrees(c, initial, metadata_only);
1816
1817         if (ret == -BCH_ERR_need_topology_repair &&
1818             !test_bit(BCH_FS_TOPOLOGY_REPAIR_DONE, &c->flags) &&
1819             !test_bit(BCH_FS_INITIAL_GC_DONE, &c->flags)) {
1820                 set_bit(BCH_FS_NEED_ANOTHER_GC, &c->flags);
1821                 SET_BCH_SB_HAS_TOPOLOGY_ERRORS(c->disk_sb.sb, true);
1822                 ret = 0;
1823         }
1824
1825         if (ret == -BCH_ERR_need_topology_repair)
1826                 ret = -BCH_ERR_fsck_errors_not_fixed;
1827
1828         if (ret)
1829                 goto out;
1830
1831 #if 0
1832         bch2_mark_pending_btree_node_frees(c);
1833 #endif
1834         c->gc_count++;
1835
1836         if (test_bit(BCH_FS_NEED_ANOTHER_GC, &c->flags) ||
1837             (!iter && bch2_test_restart_gc)) {
1838                 if (iter++ > 2) {
1839                         bch_info(c, "Unable to fix bucket gens, looping");
1840                         ret = -EINVAL;
1841                         goto out;
1842                 }
1843
1844                 /*
1845                  * XXX: make sure gens we fixed got saved
1846                  */
1847                 bch_info(c, "Second GC pass needed, restarting:");
1848                 clear_bit(BCH_FS_NEED_ANOTHER_GC, &c->flags);
1849                 __gc_pos_set(c, gc_phase(GC_PHASE_NOT_RUNNING));
1850
1851                 bch2_gc_stripes_reset(c, metadata_only);
1852                 bch2_gc_alloc_reset(c, metadata_only);
1853                 bch2_gc_reflink_reset(c, metadata_only);
1854                 ret = bch2_gc_reset(c);
1855                 if (ret)
1856                         goto out;
1857
1858                 /* flush fsck errors, reset counters */
1859                 bch2_flush_fsck_errs(c);
1860                 goto again;
1861         }
1862 out:
1863         if (!ret) {
1864                 bch2_journal_block(&c->journal);
1865
1866                 ret   = bch2_gc_stripes_done(c, metadata_only) ?:
1867                         bch2_gc_reflink_done(c, metadata_only) ?:
1868                         bch2_gc_alloc_done(c, metadata_only) ?:
1869                         bch2_gc_done(c, initial, metadata_only);
1870
1871                 bch2_journal_unblock(&c->journal);
1872         }
1873
1874         percpu_down_write(&c->mark_lock);
1875         /* Indicates that gc is no longer in progress: */
1876         __gc_pos_set(c, gc_phase(GC_PHASE_NOT_RUNNING));
1877
1878         bch2_gc_free(c);
1879         percpu_up_write(&c->mark_lock);
1880
1881         up_write(&c->gc_lock);
1882
1883         /*
1884          * At startup, allocations can happen directly instead of via the
1885          * allocator thread - issue wakeup in case they blocked on gc_lock:
1886          */
1887         closure_wake_up(&c->freelist_wait);
1888         return ret;
1889 }
1890
1891 static int gc_btree_gens_key(struct btree_trans *trans,
1892                              struct btree_iter *iter,
1893                              struct bkey_s_c k)
1894 {
1895         struct bch_fs *c = trans->c;
1896         struct bkey_ptrs_c ptrs = bch2_bkey_ptrs_c(k);
1897         const struct bch_extent_ptr *ptr;
1898         struct bkey_i *u;
1899         int ret;
1900
1901         percpu_down_read(&c->mark_lock);
1902         bkey_for_each_ptr(ptrs, ptr) {
1903                 struct bch_dev *ca = bch_dev_bkey_exists(c, ptr->dev);
1904
1905                 if (ptr_stale(ca, ptr) > 16) {
1906                         percpu_up_read(&c->mark_lock);
1907                         goto update;
1908                 }
1909         }
1910
1911         bkey_for_each_ptr(ptrs, ptr) {
1912                 struct bch_dev *ca = bch_dev_bkey_exists(c, ptr->dev);
1913                 u8 *gen = &ca->oldest_gen[PTR_BUCKET_NR(ca, ptr)];
1914
1915                 if (gen_after(*gen, ptr->gen))
1916                         *gen = ptr->gen;
1917         }
1918         percpu_up_read(&c->mark_lock);
1919         return 0;
1920 update:
1921         u = bch2_bkey_make_mut(trans, k);
1922         ret = PTR_ERR_OR_ZERO(u);
1923         if (ret)
1924                 return ret;
1925
1926         bch2_extent_normalize(c, bkey_i_to_s(u));
1927         return bch2_trans_update(trans, iter, u, 0);
1928 }
1929
1930 static int bch2_alloc_write_oldest_gen(struct btree_trans *trans, struct btree_iter *iter,
1931                                        struct bkey_s_c k)
1932 {
1933         struct bch_dev *ca = bch_dev_bkey_exists(trans->c, iter->pos.inode);
1934         struct bch_alloc_v4 a_convert;
1935         const struct bch_alloc_v4 *a = bch2_alloc_to_v4(k, &a_convert);
1936         struct bkey_i_alloc_v4 *a_mut;
1937         int ret;
1938
1939         if (a->oldest_gen == ca->oldest_gen[iter->pos.offset])
1940                 return 0;
1941
1942         a_mut = bch2_alloc_to_v4_mut(trans, k);
1943         ret = PTR_ERR_OR_ZERO(a_mut);
1944         if (ret)
1945                 return ret;
1946
1947         a_mut->v.oldest_gen = ca->oldest_gen[iter->pos.offset];
1948         a_mut->v.data_type = alloc_data_type(a_mut->v, a_mut->v.data_type);
1949
1950         return bch2_trans_update(trans, iter, &a_mut->k_i, 0);
1951 }
1952
1953 int bch2_gc_gens(struct bch_fs *c)
1954 {
1955         struct btree_trans trans;
1956         struct btree_iter iter;
1957         struct bkey_s_c k;
1958         struct bch_dev *ca;
1959         u64 b, start_time = local_clock();
1960         unsigned i;
1961         int ret;
1962
1963         /*
1964          * Ideally we would be using state_lock and not gc_lock here, but that
1965          * introduces a deadlock in the RO path - we currently take the state
1966          * lock at the start of going RO, thus the gc thread may get stuck:
1967          */
1968         if (!mutex_trylock(&c->gc_gens_lock))
1969                 return 0;
1970
1971         trace_and_count(c, gc_gens_start, c);
1972         down_read(&c->gc_lock);
1973         bch2_trans_init(&trans, c, 0, 0);
1974
1975         for_each_member_device(ca, c, i) {
1976                 struct bucket_gens *gens;
1977
1978                 BUG_ON(ca->oldest_gen);
1979
1980                 ca->oldest_gen = kvmalloc(ca->mi.nbuckets, GFP_KERNEL);
1981                 if (!ca->oldest_gen) {
1982                         percpu_ref_put(&ca->ref);
1983                         ret = -BCH_ERR_ENOMEM_gc_gens;
1984                         goto err;
1985                 }
1986
1987                 gens = bucket_gens(ca);
1988
1989                 for (b = gens->first_bucket;
1990                      b < gens->nbuckets; b++)
1991                         ca->oldest_gen[b] = gens->b[b];
1992         }
1993
1994         for (i = 0; i < BTREE_ID_NR; i++)
1995                 if (btree_type_has_ptrs(i)) {
1996                         struct btree_iter iter;
1997                         struct bkey_s_c k;
1998
1999                         c->gc_gens_btree = i;
2000                         c->gc_gens_pos = POS_MIN;
2001                         ret = for_each_btree_key_commit(&trans, iter, i,
2002                                         POS_MIN,
2003                                         BTREE_ITER_PREFETCH|BTREE_ITER_ALL_SNAPSHOTS,
2004                                         k,
2005                                         NULL, NULL,
2006                                         BTREE_INSERT_NOFAIL,
2007                                 gc_btree_gens_key(&trans, &iter, k));
2008                         if (ret && !bch2_err_matches(ret, EROFS))
2009                                 bch_err(c, "error recalculating oldest_gen: %s", bch2_err_str(ret));
2010                         if (ret)
2011                                 goto err;
2012                 }
2013
2014         ret = for_each_btree_key_commit(&trans, iter, BTREE_ID_alloc,
2015                         POS_MIN,
2016                         BTREE_ITER_PREFETCH,
2017                         k,
2018                         NULL, NULL,
2019                         BTREE_INSERT_NOFAIL,
2020                 bch2_alloc_write_oldest_gen(&trans, &iter, k));
2021         if (ret && !bch2_err_matches(ret, EROFS))
2022                 bch_err(c, "error writing oldest_gen: %s", bch2_err_str(ret));
2023         if (ret)
2024                 goto err;
2025
2026         c->gc_gens_btree        = 0;
2027         c->gc_gens_pos          = POS_MIN;
2028
2029         c->gc_count++;
2030
2031         bch2_time_stats_update(&c->times[BCH_TIME_btree_gc], start_time);
2032         trace_and_count(c, gc_gens_end, c);
2033 err:
2034         for_each_member_device(ca, c, i) {
2035                 kvfree(ca->oldest_gen);
2036                 ca->oldest_gen = NULL;
2037         }
2038
2039         bch2_trans_exit(&trans);
2040         up_read(&c->gc_lock);
2041         mutex_unlock(&c->gc_gens_lock);
2042         return ret;
2043 }
2044
2045 static int bch2_gc_thread(void *arg)
2046 {
2047         struct bch_fs *c = arg;
2048         struct io_clock *clock = &c->io_clock[WRITE];
2049         unsigned long last = atomic64_read(&clock->now);
2050         unsigned last_kick = atomic_read(&c->kick_gc);
2051         int ret;
2052
2053         set_freezable();
2054
2055         while (1) {
2056                 while (1) {
2057                         set_current_state(TASK_INTERRUPTIBLE);
2058
2059                         if (kthread_should_stop()) {
2060                                 __set_current_state(TASK_RUNNING);
2061                                 return 0;
2062                         }
2063
2064                         if (atomic_read(&c->kick_gc) != last_kick)
2065                                 break;
2066
2067                         if (c->btree_gc_periodic) {
2068                                 unsigned long next = last + c->capacity / 16;
2069
2070                                 if (atomic64_read(&clock->now) >= next)
2071                                         break;
2072
2073                                 bch2_io_clock_schedule_timeout(clock, next);
2074                         } else {
2075                                 schedule();
2076                         }
2077
2078                         try_to_freeze();
2079                 }
2080                 __set_current_state(TASK_RUNNING);
2081
2082                 last = atomic64_read(&clock->now);
2083                 last_kick = atomic_read(&c->kick_gc);
2084
2085                 /*
2086                  * Full gc is currently incompatible with btree key cache:
2087                  */
2088 #if 0
2089                 ret = bch2_gc(c, false, false);
2090 #else
2091                 ret = bch2_gc_gens(c);
2092 #endif
2093                 if (ret < 0)
2094                         bch_err(c, "btree gc failed: %s", bch2_err_str(ret));
2095
2096                 debug_check_no_locks_held();
2097         }
2098
2099         return 0;
2100 }
2101
2102 void bch2_gc_thread_stop(struct bch_fs *c)
2103 {
2104         struct task_struct *p;
2105
2106         p = c->gc_thread;
2107         c->gc_thread = NULL;
2108
2109         if (p) {
2110                 kthread_stop(p);
2111                 put_task_struct(p);
2112         }
2113 }
2114
2115 int bch2_gc_thread_start(struct bch_fs *c)
2116 {
2117         struct task_struct *p;
2118
2119         if (c->gc_thread)
2120                 return 0;
2121
2122         p = kthread_create(bch2_gc_thread, c, "bch-gc/%s", c->name);
2123         if (IS_ERR(p)) {
2124                 bch_err(c, "error creating gc thread: %s", bch2_err_str(PTR_ERR(p)));
2125                 return PTR_ERR(p);
2126         }
2127
2128         get_task_struct(p);
2129         c->gc_thread = p;
2130         wake_up_process(p);
2131         return 0;
2132 }